The invention is in the field of outdoor advertising and particularly pertains to billboards.
Current billboard installations are expensive, running into tens of thousands of dollars in some instances. The advertising copy on a billboard must be changed every several weeks to maximize advertising efficiency, as the public passing the particular billboard becomes saturated within that time.
This necessitates frequent billboard changes. Two techniques of changing billboards involve pasting on paper segments of the billboard and, more currently, pre-painted plywood sections are being used because they are more durable than paper and do not tear.
In addition to the initial cost of a billboard installation and the cost and difficulty of the frequent periodic rotation of advertisements that must take place, an increasing problem is being encountered pertaining to laws and local ordinances prohibiting, limiting, or requiring licensing of billboards and other forms of advertising. Often these regulations relate to the degree of permanency of advertising matter, being more stringent the more permanent the advertising installation becomes. Regulations vary from outright bans of billboards along interstate highways, to restrictions on sign styles and size above a business establishment.
However, it has been found unconstitutional to ban advertising on the sides of motor vehicles, and generally speaking portable billboards, at least arguably, fall within the same exception to billboard and sign restrictions. This had led to the creation of sign companies which mount billboards and signs on trailers which are parked in front of business establishments to advertise products and promotions.